1. Yalta Conference (February 1945): During World War II, the Soviet Union and the Western Allies (United States, United Kingdom, and France) held a series of conferences to discuss post-war arrangements. At the Yalta Conference, the leaders of these countries agreed to divide Germany into four occupation zones, and the Soviet Union would control Eastern Europe to ensure its security against future German aggression.
2. Iron Curtain Speech (March 1946): In a famous speech at Westminster College in Fulton, Missouri, former British Prime Minister Winston Churchill used the term "iron curtain" to describe the political division between the Soviet-controlled Eastern Europe and the democratic Western Europe.
3. Truman Doctrine (March 1947): In response to the Soviet Union's expansion of influence in Eastern Europe and its support for communist parties, US President Harry S. Truman announced the Truman Doctrine, pledging to support free peoples resisting subjugation by armed minorities or outside pressures.
4. Marshall Plan (June 1947): The United States launched the Marshall Plan, a massive economic aid program, to help Western Europe rebuild after the war. The Soviet Union opposed this plan, as it feared it would increase Western influence in Eastern Europe.
5. Berlin Blockade and Airlift (1948-1949): In June 1948, the Soviet Union blocked all land and water routes from the Western-occupied zones of Germany into West Berlin. In response, the Western Allies organized a massive airlift operation, known as the Berlin Airlift, to supply the city. The Soviet Union eventually lifted the blockade in May 1949.
6. Formation of NATO and Warsaw Pact (1949): In response to the Soviet threat, the Western Allies established the North Atlantic Treaty Organization (NATO), a collective security alliance. Soon after, the Soviet Union and its Eastern European allies formed the Warsaw Pact, a rival military alliance.
7. Division of Germany (1949): The division of Germany into two separate states, the Federal Republic of Germany (West Germany) and the German Democratic Republic (East Germany), was formalized in 1949. Berlin, the former capital of Germany, was also divided into East and West Berlin.
These events and developments solidified the division of Europe into the communist East and the democratic West, which persisted until the collapse of communist regimes in Eastern Europe in 1989 and the reunification of Germany in 1990.